Two hundred and ten species of marine algae, seagrasses and cyanobacteria are reported from the Dampier Archipelago, northwestern Western Australia. Included are 114 species of Rhodophyta, 50 species of Chlorophyta, 32 species of Phaeophyceae, 5 species of Cyanophyta and 9 species of seagrasses. This report presents the first detailed account of marine benthic algae from tropical Western Australia. Fifty-seven species are newly recorded for Western Australia, with five species (Codium dwarkense, Dictyota friabilis, Balliella subcorticata, Cottoniella amamiensis, Polysiphonia pentamera) also newly recorded for Australia. The algal flora of the region includes many elements common to tropical areas worldwide
